Disposable diaper with twist tab fastener

ABSTRACT

A disposable diaper having a moisture-impermeable backing sheet and an absorbent pad superposed on the backing sheet is provided with tab-type fasteners which do not require a release sheet for protecting adhesive surfaces thereof. Each fastener is secured to the backing sheet and comprises a pair of relatively wider terminal portions and a relatively narrow, twistable and flexible central segment which connects the terminal portions. One of the terminal portions is attached to the backing sheet and the other, free terminal portion is removably attached to a release surface provided on the terminal portion which is attached to the backing sheet.

United States Patent Tritsch Dec. 16, 1975 [75] Inventor: Ludwig Tritsch, Wilmette, Ill.

[73] Assignee: Johnson & Johnson, New

Brunswick, NJ.

[22] Filed: Nov. 20, 1974 [21] Appl. No.: 525,536

[52] US. Cl. 128/287; 128/284; 24/67 [51] Int. Cl. A61F 13/16 [58] Field of Search 128/284, 287, 290 R; 24/67 [56] References Cited UNITED STATES PATENTS 3,642,001 2/1972 Sabee 128/287 3,875,621 4/1975 Karami 4. 24/67 Primary ExaminerAldrich F. Medbery 5 7 ABSTRACT A disposable diaper having a moisture-impermeable backing sheet and an absorbent pad superposed on the backing sheet is provided with tab-type fasteners which do not require a release sheet for protecting adhesive surfaces thereof. Each fastener is secured to the backing sheet and comprises a pair of relatively wider terminal portions and a relatively narrow, twistable and flexible central segment which connects the terminal portions. One of the terminal portions is attached to the backing sheet and the other, free terminal por tion is removably attached to a release surface provided on the terminal portion which is attached to the backing sheet.

8 Claims, 5 Drawing Figures US. Patent Dec. 16, 1975 [III/III] DISPOSABLE DIAPER WITH TWIST TAB FASTENER BACKGROUND OF THE INVENTION This invention relates to disposable diapers. More particularly, this invention relates to disposable diapers adapted to be secured in place by adhesive tabs.

Disposable diapers provide substantial advantages in convenience over conventional diapers and commonly have a generally quadrilateral configuration with straight or curvilinear longitudinal edges. Disposable diapers are conveniently secured about an infant by means of adhesive tape tabs which are affixed to the di' aper along a longitudinal edge thereof, thus eliminating the need for extraneous fasteners, such as pins. In order to protect the adhesive surfaces of the tape tabs, usually a release sheet is applied over these adhesive surfaces for subsequent removal when the diaper is about to be used. However, such tabs usually project beyond the confines of the diaper to a considerable extent and interfere with the efficient manufacture and packaging of the diaper.

In an attempt to solve the foregoing problems, US. Pat. No. 3,776,234 to Hoey proposes to fold the tab over on itself at the diapers edge and to adhesively attach a portion of the folded-over tab segment to the inside surface of the diaper in order to keep the tab from interfering with the manufacturing machinery and with the folding and packaging operations. This requires that the edge of the diaper backing sheet be folded over to present an attachment surface at the front or inside face of the diaper and a relatively involved tab design is necessary for this purpose. Also, undesirable tearing of the diaper facing fabric may result if such a tab is adhesively attached to the facing fabric of the diaper.

One of the most convenient adhesive systems that has been developed to date is one in which adhesive tabs are adhered to the backing sheet extending outwardly from opposite sides of the diaper at one end thereof, and in which the exposed tacky areas of the adhesive strips are provided with readily separable cover strips which protect the exposed areas until ready for use. However, disposable diapers using an adhesive closure system of this general type have the disadvantage that the consumer has to dispose of the cover strips when they are separated from the adhesive tabs. This is an inconvenience to the consumer who is placing the diaper on a baby at about the same time.

US. Pat. No. 3,646,937 to Gellert shows a fastening tab which is provided with a release surface which is permanently bonded to the inside surface of the diaper; however, such an arrangement is disadvantageous be cause the release surface may be placed in contact with the infants skin when the diaper is used.

SUMMARY OF THE INVENTION The present invention contemplates a diaper having adhesive tab-type fastener which does not require a release sheet to protect the adhesive surface thereof. The disposable diaper embodying the present invention comprises a thin, flexible backing sheet of substantially moisture-impermeable material, a moisture-retaining layer including a pad or absorbent material which is superposed on the backing sheet and attached thereto, and a fastening tab means which is secured to the backing sheet and includes a pair of relatively wider terminal portions and a relatively narrow, twistable and flexi- 'ble central segment which connects the terminal portions. One of the terminal portions is attached to the backing sheet and is provided with an outwardly-facing release surface, and the other, free terminal portion bears a layer of pressure-sensitive adhesive for attachment to the diaper when the diaper is applied to the infant. The free terminal portion is removably attached to the aforesaid release surface on the terminal portion which is attached to the diaper backing sheet.

BRIEF DESCRIPTION OF THE DRAWING In the drawing,

FIG. 1 is a perspective view of a disposable diaper embodying the present invention in a configuration assumed by the diaper when placed about an infant;

FIG. 2 is a broken plan view of the diaper shown in FIG. 1;

FIG. 3 is a partial sectional elevation on an enlarged scale taken along plane 3-3 in FIG. 2;

FIG. 4 is a sectional elevation similar to that of FIG. 3 but showing the tab-type fastener before it is extended prior to use; and

FIG. 5 is a partial sectional elevation on an enlarged sca'le taken along plane 5-5 in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, disposable diaper 10, having a substantially quadrilateral configuration and presenting inside surface 11 for direction toward an infant and outside surface 12 for direction away from the infant is provided with adhesive tabs 13 and 14 which can be made of polyethylene sheet, polypropylene sheet, or similar materials. As illustrated by tab 13, the fastening means comprises relatively wider free terminal portion 15 and relatively wider fixed terminal portion 16. These terminal portions are connected by a relatively narrower, twistable and flexible central segment 17 which is shorter than free terminal portion 15. Similarly, tab 14 is provided with fixed terminal portion 18, free terminal portion 19 and central segment 20 connecting portions 18 and 19. Tabs 13 and 14 are attached to diaper 10 by securing terminal portions 16 and 18, respectively, to backing sheet 21 (FIG. 1) which forms outside surface 12 of the diaper. Preferably, the relative widths of the free terminal portion and the central segment are in a ratio of at least about 3:1, respectively. Additionally, for ease of manipulation it is preferred that the free terminal portion is somewhat smaller than the fixed terminal portion.

Referring to FIG. 3, tab 13 is attached to backing sheet 21 by means of adhesive layer 24. In the case of a thermoplastic tab material, attachment can also be effected by heat-sealing or similar means. The moisture-retaining layer of diaper 10, superposed on backing sheet 21, comprises absorbent pad means 22 covered by facing sheet 23. Release surface 25 is provided on terminal portion 16 and faces in the same direction as the outer surface of backing sheet 21. Pressure-sensitive adhesive layer 26 is provided on free terminal portion 15 and faces in the same direction as release surface 25. Before the diaper is prepared for use, adhesive layer 26 is protected by removable attachment to release surface 25. This can be readily accomplished by simply folding central segment 17 back on itself so that adhesive layer 26 is in juxtaposition with and contacts release surface 25. When diaper 10 is prepared for use, terminal portion 15, bearing adhesive layer 26, is

pulled free from release surface 25 of attached terminal portion 16, and central segment 17 is twisted about one-half turn so that adhesive layer 26 faces in the same direction as diaper inside surface 11 formed by facing sheet 23.

The configuration assumed by the fastener means when ready for use is illustrated in FIG. which shows tab 14 having exposed adhesive layer 28 facing in the same direction as inside surface 11. Central segment is convoluted as a result of terminal portion 19 having been turned about 180. The corresponding attached terminal portion 18 remains secured to backing sheet 21 by means of adhesive layer 27, and release surface 29, which previously protected pressure-sensitive adhesive layer 28, remains on terminal portion 18, on the side thereof opposite to that attached to backing sheet 21.

In a further embodiment of this invention, fastener means such as tab 13 can be provided with a pressuresensitive adhesive layer on surface 30 in lieu of adhesive layer 26 shown in FIGS. 3 and 4. The tab modified in this manner is provided with a pressure-sensitive adhesive layer on the side thereof opposite to that bearing a release surface such as surface in FIG. 3. The adhesive layer provided on surface is protected by removable attachment to release surface 25 by twisting central segment 17 about onehalf turn and juxtaposing surface 30 contiguous with surface 25. When the tab modified in the foregoing manner is utilized to affix a diaper about an infant, no convolution is present in the central segment thereofyhowever, the segment is convoluted while surface 30 is adhesively but removably attached to release surface 25.

In yet another embodiment of the present invention the twistable central segments such as segment 17 (FIG. 3) and segment 20 (FIG. 5) can be formed of an extensible elastic material, for example, rubber, a polyurethane elastomer, a butadiene-styrene block polymer elastomer, or the like. While the disposable diaper usuallyis relatively inelastic, the elasticity of. the central segment in this particular embodiment permits the applied diaper to expand and contract about the waist of the infant, thereby accommodating the infants movements as well as breathing action and thus contributing to comfort. Elasticity can also be imparted to the central segment of the tab by selecting a semielastic material for the entire tab, for example, polyethylene sheet, or the like, because the substantially hour-glass configuration of the tab permits the central segment to elongate in response to a given applied tensile force to a greater degree than the relatively wider terminal portions of the tab. Also, a scrim or similar reinforcing material can be provided for the terminal portions to render these portions less elastic.

A suitable backing sheet for the diaper embodying the present invention can be an opaque polyethylene web about 0.001 inch thick. Another suitable sheet material for this purpose is a polyethylene terephthalate web having a thickness of about 0.0005 inch.

Several different types of facing materials may be used for diaper facing sheet 23. For example, facing sheet 23 may be made up of a mixture of fibers consisting predominantly of inexpensive short cellulosic fibers, such as wood pulp fibers or cotton linters, in amounts of about 75 percent to about 98 percent, the balance being textile length fibers such as rayon as described in US. Pat. No. 3,663,348 to Liloia et al.

Facing sheet materials suitable for use in this invention have fabric weights in the range of about 1 to 5 oz.- /yd. and densities of less than 0.15 g./cc., generally in the range between 0.05 and 0.1 g./cc. The dry strength of the facing sheet for a fabric having a weight of about 1.5 oz./yd. is at least 0.15 lbs./in. of width in the machine direction and at least 0.1 lbs/in. of width in the cross direction. Such fabrics have unusually good elongation, loft, softness, and drape characteristics in comparison to prior products incorporating any substantial amount of short fibers.

Facing layer 23 may also be made of an apertured, nonwoven fabric which is formed, for example, in accordance with the teachings in commonly assigned US. Pat. Nos. 2,862,251; 3,081,514; and 3,081,515. Briefly, such fabrics are foraminous structures wherein groups or groupings of fibers have been rearranged from a fibrous nonwoven starting web into positions surrounding less dense fabric portions by passage of a fluid through the starting material. The fibers within the groupings are mechanically interlocked, and may be arranged into various patterns, as is well known by those skilled in the art. A suitable binder may be uti lized to help retain the fibers in their rearranged locations, as is also well known by those skilled in the art. The fabric can be made of naturally occurring fibers, synthetic fibers or blends thereof. Typical facing layers made of a polyester-type material can have a weight of oz./yd.

In addition, facing sheet 23 can be formed of a non apertured material, such as a nonwoven isotropic web, sponge, or the like. In all of the aforementioned facings, the materials should be relatively hydrophobic so as to retard wicking within the facing layer.

Highly moisture-absorbent fibrous pad or batt 22 which is substantially rectangular in shape, but smaller than the facing and backing sheet, is centrally disposed therebetween. Pad 22 can be formed in accordance with the teachings of US. Pat. No. 3,612,055 to Mesek et al. Alternatively, a higher moisture-absorbent layer can be provided substantially coextensive with backing sheet 21 if desired.

Typical disposable diapers which can be fitted with a tab-type fastener described hereinabove are shown in Us. Pat. 3,612,055 to Mesek et a1. and in US. Pat. No. 3,683,916 to Mesek et al. Other suitable disposable diaper structures are shown in US. Pat. No. Re. 26,151 to Duncan et a1.

Release properties to attached terminal portions 16 and 18 can be imparted to the outer surfaces thereof by coating these surfaces with a silicone compound, or the like, or by affixing a sheet of suitable release paper thereto.

The pressure-sensitive adhesive layers such as layer 26 and layer 28 are provided by applying a pressuresensitive adhesive known in the art. The applied adhesive shall have good tack, good cohesive strength, good resistance to moisture and good resistance to aging. lllustrative of such adhesives are mixtures of natural or synthetic rubber, zinc oxide, and various resins, also latices of natural or synthetic rubber, or water dispersions of acrylic tacky polymers or copolymers.

In use, a diaper equipped with the fasteners of this invention is applied to the infant by laying out the diaper on a suitable flat surface and placing the infant thereon so that the waist-underlying end of the diaper is that having the fastener means. The other end of the diaper then extends downwardly between the infants legs.

Next, the downwardly-extending end of the diaper is brought up between the infants legs to a position contiguous with the front of the infants waist. The diaper is thereafter secured to the infant by placing the corners of the waist portion of the abdomen-covering end as far around the infants waist as they will go and by bringing the corners of the underlying end of the diaper into an overlapping relationship with the aforementioned corners so that the diaper snugly encircles the infants waist. The removably attached terminal portions of the fastener means are then lifted from the corresponding release surfaces thereof and are adhesively fixed in a desired position on the backing sheet of the abdomen-covering end by simply urging the pressuresensitive adhesive surfaces in contact therewith.

The foregoing description and the drawing are illustrative but are not to be taken as limiting. Still other variations and modifications are possible without departing from the spirit and scope of the present invention.

I claim:

1. In combination with a disposable diaper of substantially quadrilateral configuration, having an inside surface for direction toward an infant when the diaper is worn by that infant and an outside surface for direction away from said infant, and including a thin, flexible backing sheet of substantially moisture-impermeable material defining said outside surface and a moistureretaining layer having a pad of absorbent material superposed on said backing sheet and attached thereto, a fastening tab means secured to the backing sheet adjacent one end thereof and comprising a pair of relatively wider terminal portions and including a means for adjustably positioning one of said terminal portions to temporarily attach it to the diaper comprising a relatively narrower, twistable and flexible central segment connecting the terminal portions; the other of said terminal portions being fixedly, attached on one side to said backing sheet and having an outwardly-facing release surface, on the other side, said one terminal portion bearing a layer of pressure-sensitive adhesive for attachment to the outside surface of the diaper adjacent a second end thereof when the diaper is applied to the infant and also positionable for removable attachment to said release surface by means of the adhesive layer thereon.

2. The combination in accordance with claim 1 wherein said release surface on the attached teminal portion and said adhesive layer on the free terminal portion are situated on opposite sides of said fastening tab means.

3. The combination in accordance with claim 2 wherein said central segment is twisted about one-half turn and said free terminal portion is removably attached to said release surface.

4. The combination in accordance with claim 1 wherein said release surface on the attached terminal portion of said adhesive layer on the free terminal portion are situated on the same side of said fastening tab means.

5. The combination in accordance with claim 4 wherein said central segment is folded back on itself and said free terminal portion is removably attached to said release surface.

6. The combination in accordance with claim 1 wherein said central segment is freely extensible and elastic.

7. The combination in accordance with claim 1 wherein the attached terminal portion is provided with an adhesive layer on the side thereof opposite to that having the release surface and wherein the attached terminal portion is adhesively secured to the backing sheet.

8. The combination in accordance with claim 1 wherein the width ratio of the free terminal portion to the central segment is at least about 3:1. 

1. In combination with a disposable diaper of substantially quadrilateral configuration, having an inside surface for direction toward an infant when the diaper is worn by that infant and an outside surface for direction away from said infant, and including a thin, flexible backing sheet of substantially moisture-impermeable material defining said outside surface and a moisture-retaining layer having a pad of absorbent material superposed on said backing sheet and attached thereto, a fastening tab means secured to the backing sheet adjacent one end thereof and comprising a pair of relatively wider terminal portions and including a means for adjustably positioning one of said terminal portions to temporarily attach it to the diaper comprising a relatively narrower, twistable and flexible central segment connecting the terminal portions; the other of said terminal portions being fixedly, attached on one side to said backing sheet and having an outwardly-facing release surface, on the other side, said one terminal portion bearing a layer of pressure-sensitive adhesive for attachment to the outside surface of the diaper adjacent a second end thereof when the diaper is applied to the infant and also positionable for removable attachment to said release surface by means of the adhesive layer thereon.
 2. The combination in accordance with claim 1 wherein said release surface on the attached teminal portion and said adhesive layer on the free terminal portion are situated on opposite sides of said fastening tab means.
 3. The combination in accordance with claim 2 wherein said central segment is twisted about one-half turn and said free terminal portion is removably attached to said release surface.
 4. The combination in accordance with claim 1 wherein said release surface on the attached terminal portion of said adhesive layer on the free terminal portion are situated on the same side of said fastening tab means.
 5. The combination in accordance with claim 4 wherein said central segment is folded back on itself and said free terminal portion is removably attached to said release surface.
 6. The combination in accordance with claim 1 wherein said central segment is freely extensible and elastic.
 7. The combination in accordance with claim 1 wherein the attached terminal portion is provided with an adhesive layer on the side thereof opposite to that having the release surface and wherein the attached terminal portion is adhesively secured to the backing sheet.
 8. The combination in accordance with claim 1 wherein the width ratio of the free terminal portion to the central segment is at least about 3:1. 